float aggr_;

my_plugin_aggregator() : aggr_(0) {}

std::string name() const {

return "aggregator";

}

float calculate(float x, float y) {

aggr_ += x + y;

return aggr_;

}

// Factory method

static boost::shared_ptr<my_plugin_aggregator> create() {

return boost::shared_ptr<my_plugin_aggregator>(

new my_plugin_aggregator()

);

}